Voltage-to-current conversion circuit and OTA using the same

An OTA that generates an output current in accordance with the difference voltage between a first input voltage and a second input voltage, comprising a first voltage-to-current conversion circuit that generates a first output current in accordance with the first input voltage;

• a second voltage-to-current conversion circuit that generates a second output current in accordance with the second input voltage;
• and
• a difference output operation circuit that performs the operation to calculate the difference current between the first output current and the second output current, and
• wherein each of the first voltage-to-current conversion circuit and the second voltage-to-current conversion circuit comprises a first MOSFET, to which a fixed drain-source voltage is applied all the time and which generates a first current signal for the input voltage, a second MOSFET, which has the same polarity as that of the first MOSFET, to which the fixed drain-source voltage is applied all the time, and which generates a second current signal that is complementary to the first current signal for the input voltage, and a difference current operation circuit that performs the operation of subtraction between the first current signal and the second current signal.